This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Assembly and disassembly of a viral capsid, or a protein shell, are essential steps in the life cycle of a virus. Understanding of viral assembly/disassembly can provide additional insights to other oligomerization processes as in protein association in large cellular assemblies, which occurs through a similar mechanism. Additionally, understanding the properties and function of the capsid shell alone is important for inferring all steps involved in host cell entry and release of the enveloped genetic material and can aid in proposing efficient ways of interfering with capsid assembly and stability via structure-based design of antiviral therapeutics. One of the most intensely studied viruses has been the cowpea chlorotic mottle virus (CCMV), a positive strand RNA plant-infecting virus which belongs to the Bromoviridae family. It is composed of a protein capsid and viral RNA which is packed inside. It has been widely used as a model system for understanding of biological assembly because of its icosahedral structure and the limited number of gene products required for its assembly. CCMV offers an accessible model system for examining the processes that regulate viral assembly, disassembly, and stability, both for theoretical and experimental studies.